Put a little RTV sealant on the plug every time you fill up to prevent leaking, that's what I do <img src="/forums/images/graemlins/notooth.gif" alt="" />. Other than that you would probably have to tap the cover to accept a screw in plug or get an aftermarket diff cover, those usually have threaded plugs. Hope this helps.

Fred R.

97 ZJ, 5" Long Arm Lift, Beadlocked 35's, 231/D300 Doubler, Locked Front & Rear (Narrowed HP D44 & F8.8), ARB Bull Bar & 9K winch, 1-Ton Hydro-assist steering, "Custom" body work and some other goodies... PICS